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c21 · 10-09-2013, 01:32 PM

I want to thank everyone who has contributed to the various posts regarding battery discharge rates. In my case, with my 2014 AI Twin, the culprit was the antenna booster. My batteries are now holding just fine while parked under my carport. The one thing I don't understand (and perhaps a knowlegable member can enlighten me) why, when plugged into 110, do the batteries charge to 100% in the bulk and absorbtion stages then drop to 90% in the float stage? Is it advisable to try to catch it at or near 100% and unplug?
Thanks in advance.
Bill

wayneskid · 10-10-2013, 08:30 AM

Bill, where are you getting the SOC % readings? And which inverter/charger do you have in your Interstate?

c21 · 10-10-2013, 11:36 AM

I have the Magnum 1000w invertor/charger and the SOC reading is off the solar charge indicator. I noticed it read 100% during absorbtion stage then dropped to 90% during float stage. This is what the manual said it was supposed to do but I don't understand why.

UKDUDE · 10-10-2013, 12:44 PM

Hello Bill, I was new to all of this 6 months ago - but I'm learning fast....
If you refer to the Lifeline Technical Manual - which you can download from the Lifeline website - you can see that Lifeline endorses this method of charging their batteries. But you will read that the voltage rates are all dependent on the ambient temperature. Float is supposed to maintain a 100% charge - but with a reduced voltage.
I suspect you may have to adjust your Magnum settings to take the ambient temperature into account.
Peter

lewster · 10-10-2013, 01:01 PM

Quote:

Originally Posted by UKDUDE

Hello Bill, I was new to all of this 6 months ago - but I'm learning fast....
If you refer to the Lifeline Technical Manual - which you can download from the Lifeline website - you can see that Lifeline endorses this method of charging their batteries. But you will read that the voltage rates are all dependent on the ambient temperature. Float is supposed to maintain a 100% charge - but with a reduced voltage.
I suspect you may have to adjust your Magnum settings to take the ambient temperature into account.
Peter

All Magnum inverter/chargers come with a temperature sensor that is connected to a negative battery terminal. This is plugged it to the network port on the Magnum, which then will automatically compensate the charging voltage according to the ambient battery temps read by the sensor.

No other adjustments are required, so long as you have programmed the remote with the proper battery type.

c21 · 10-10-2013, 03:13 PM

Thanks lewster and ukdude, your feedback is much appreciated.

Boxster1971 · 10-10-2013, 05:54 PM

Quote:

Originally Posted by lewster

All Magnum inverter/chargers come with a temperature sensor that is connected to a negative battery terminal. This is plugged it to the network port on the Magnum, which then will automatically compensate the charging voltage according to the ambient battery temps read by the sensor.

No other adjustments are required, so long as you have programmed the remote with the proper battery type.

But on my unit Airstream did not install the temp sensor for the Magnum inverter/charger. Guess I'll have to install one myself if I want the Magnum to work properly.

UKDUDE · 10-10-2013, 06:50 PM

Thanks Mike - thought I was going crazy looking for it on my unit!
Peter

c21 · 10-10-2013, 07:24 PM

Haven't checked mine yet but I will do so tomorrow. It would be a shame if Airstream simply didn't bother installing the temp sensor as they are supplied with the invertor/chargers. If anyone gets any info on ordering this part from Magnum, please share it on this thread.

c21 · 10-11-2013, 10:12 AM

Just checked my batteries and didn't see anything extra connected to the (-) terminals. Checked the invertor/charger and there is a line connected to the temp sensor terminal with the lead running toward the battery box. I assume the temp sensor lead is connected to a neg cable somewhere besides the battery terminals. Was very impressed with how the batteries were installed in a sealed, vented steel box and very neatly cabled. The quaility on these coaches is amazing.

73shark · 10-11-2013, 10:45 AM

Is there an easy way to test the AGM batteries to see how much life they have left in them?

c21 · 10-11-2013, 02:24 PM

I was mistaken about something being connected to my temp sensor input on the Magnum, it was actually the line to the remote control. There is nothing connected to the temp sensor input. I emailed Airstream tech support and they told me it was an option with the Magnums and they didn't use them. I then called Magnum tech support and was told they ship a temp sensor with every invertor they sell and although is is not mandatory to use it, they recommend installing it. They won't sell direct to the public so I called one of their dealers who quoted $32 + $20 shipping. I have emailed back to airstream and asked them to send me one of the hundreds they must have laying around. I'll report what I hear back.

c21 · 10-11-2013, 05:19 PM

Haven't heard back from Airstream but one issue that comes to mind: the batteries are contained in a sealed box. Need to somehow penetrate the box with the temp sensor lead so the box can remain sealed. This may be the reason that Airstream didn't use the temp sensors. Any ideas?

UKDUDE · 10-11-2013, 05:27 PM

I had a similar question on the forum a little while back - I wanted to connect up a trickle charger...
http://www.airforums.com/forums/f240...ox-110495.html
Peter

Boxster1971 · 10-11-2013, 07:29 PM

Quote:

Originally Posted by c21bill

Haven't heard back from Airstream but one issue that comes to mind: the batteries are contained in a sealed box. Need to somehow penetrate the box with the temp sensor lead so the box can remain sealed. This may be the reason that Airstream didn't use the temp sensors. Any ideas?

I just added a temp sensor for the new Blue Sky Solar controller I'm adding to my rig. I used a grommet that gave a reasonably tight fit on the temp sensor cable and then drilled an appropriate hole in the side of steel battery box next to the negative terminal on the rear battery in the box. See attached photo.

Enjoy,

Boxster1971 · 10-11-2013, 08:12 PM

I just looked at the installation manual and noticed that the Magnum temp sensor has an RJ11 connector on the end. So it will take a larger hole on the battery box than I was able to use for my Blue Sky Temp sensor, which has no connector on the end.

After drilling a larger hole for size of RJ11 connector one would have to use some sort of sealant to seal the battery box. I would not recommend leaving large opening that defeat the sealed battery box.

I'm probably going to also add a Magnum Temp Sensor as I want optimal battery charging at all times. I use my Interstate in all kinds of weather with wide temp swings.

lewster · 10-11-2013, 08:44 PM

You can easily cut the RJ-11 connector off of the cable, run it thru a smaller hole and then replace the connector.

A cheap set of connector pliers will do the trick. Just be sure that you get the orientation of the connector exactly the same along with the wire colors.

Plus, this will allow you to shorten the cable to the length that you need.

I find it totally reprehensible that Airstream does not connect the temp sensor, but then they could have continued giving you those POS Parallax single voltage converters!

OOPS! They still use them in the trailers. My BAD!

c21 · 10-14-2013, 09:59 AM

Just heard back from Airstream Support and contrary to what the Magnum rep told me Airstream claims that they don't receive the temp sensors with the invertor/chargers. If anyone finds a deal on these, please post it. I checked one place and they wanted $32 + $20 shipping which seems a bit spendy for what it is.

c21 · 10-14-2013, 11:51 AM

Here it is folks: I just ordered a Battery Temperature Sensor from a Company in Arizona called Tekris Power Electronics, Inc (wwww.tekrispower.com). You can call them at (877) 483-5747. I spoke to Shari and she is sending me one for $27 with free shipping. The Magnum part number is ME-BTS-15.

lewster · 10-14-2013, 01:28 PM

Having been to the Magnum factory several times (most recently in early Sept. ) and watching the production line and packing operations, I find it rather hard to believe that Magnum would do a special packaging just for Airstream, considering that every other OEM that uses Magnum inverters gets the BTS included with the units they order.

I just opened one 20 minutes ago and guess what? The BTS was right where it always is.

Just my casual observation.